Automatic refrigeration system



March 1 1927.

G'. HILGER VAUTOMATIC REFRIGERATION SYSTEM 2 sheets-snoei 1 ofginal rileva 1.20, 192s G. HILGER AUTOMATI C REFRIfGERATION SYSTEM drfginal Filed Aug. 20. 1923 2A Sheets-Shoot 2 xn www be governed by Patented Mar. 1, 1927.

GEORGE HILGER, 0F CHICAGO, ILLINOIS.

AUTOMATIC REFRIC'EBATION SYSTEM.

Application led August 20, 1923,

The invention pertains to refrigeration systems of the compression type, and has for its general aim` the pro-duction of an improved system to the end that a substantial saving may be effected through the increased efficiency of the apparatus.

Refrigeration systems arecommonly operated with a substantial loss in eiiiciency due to the fact that it is impracticable with the systems as at present constructed, to control the flow of the ammonia refrigerantv or other refrigerant to meet the varying re uirements of a series of chambers being re rigerated. Thus, if the expansion valve is set so that pressure of the refrigerant is made high enough toeffect a rapid freezing of all of the coils, the temperature of the refrigerant 4is correspondingly increased, thus lowering its 'cooling eli'ect, and further, there is danger that when the coils have become frozen an objectionable freezingback to thev compressor will result. On the other hand, when' the valve is set to supply the refrigerant at a low pressure, the freezing of the several coils occurs so slowly that some of them remain practically inoperative for a substantial portion of the period of operation.

' The primary object o f my invention is to provide for the automatlc control of the flowk of the refrigerant through the cooling coils, operating to supply the refrigerant initially at a pressure such as to effect a freezing of all of the coils as rapidly as possible, and

then at a reduced pressure, thus insuring the operation of the system as a whole durin substantiall the entire operating period an under conditions closely approaching the ideal forA maximum eiciency.

More specifically stated, the invention has for its principal object the provision of automatically operable valve means arranged to temperature variations in the system, whereby to regulate the flow of the refrigerant in accordance with the varying requirements.

A further object is to provide in a refrigeration system means controlled by the temperature in a storage room, which is adapted to restrictand entirely cut olf the flow of refrigerant to such room when the temperature falls to a predetermined degree.

Another object is to provide a means of fthe character last above mentioned including recompression.

serial No. 058,254. Renewed october a, 1926.

a three-way valve which remains at. all times in a balanced condition whereby to facilitate its automatic operation.

, Still another saving in power by the provision of a means for automatically interrupting the operation of the electric motor employed for operating the compressor when the storage room or rooms have been sufliciently cooled.

In the 'accompanying drawings, Fig. 1 is a diagrammatic illustration of a refrigeration system embodying my invention. Fig. 2 is a fragmentary vertical sectional v1ew through my improved automatic control valve. Fig. 3` is a vertical sectional view through the three-way valve. Fig. 4 is a vlew partially in elevation illustrating the meansl for automatically operating the threeobject is to effect a further way valve and a switch for-controlling the motor line circuit.

,Referring now to Fig. 1, the system comprises a compressor A actuated by an electric motor B receiving current through a line C. The compressor A discharges into a condenser D, whlch in turn discharges into a li uid receiver E. From the receiver the liquid flows b way of a pipe F to the expansion valve in icated at G; and from the latter the ammonia discharges under the control of an automaticvalve 7 into the main pipe line H.` I, storage rooms each having a cooling element or coil J communicating at its opposite ends with the pipe line H which finally returns the expanded gas to the compressor A for The compressor A, actuating motor B, condensers D, li uid receiver E'and expansion valve G, may e of any suitable or preferred construction.

The controlling valve 7 (Fig. 2) comprises a sectional casing, including an upper section 8 and lower section 8a; Between said sections, a diaphragm 9 is interposed so as to be secured mposition. Said diaphragm forms with the lower section of the casing 'a closed chamber 10, and operatively associated with the diaphragm in the upper section of the casing is a valve 11, arranged to control the flow of refrigerant, entering an inlet port 12 into which the pipe F disoutlet port 13 leading to the pipe line'H.

In the present instance, the diaphragm 9 I and I indicate three` charges, through a central port 11,fto an p t is responsive to variations in the temperaexpansion element such as ammonia gas K therein; but it will be apparent that any other suitable means responslve to temperature changes may be employed for actuating the valve 11.

The diaphragm 9 is in accordance with the present arrangement, preferably formed of two thin flexible discs 9a spaced apart and having interposed therebetween suitable insulating material 9". A spacing member 9e may also be employed to insure that the discs shall be maintained in properly spaced relation). This construction of the diaphragmit will be seen is such as to reinforce 1t, each'of the discs serving to transmit the pressure uniformly throughout .its area, to the other disc through the insulating material andv said spacer member.

The connection between the diaphragm and the valve member 11 consists of a bearing member 9c acting through a stem 9d upon the valve member 11, said stem passing through the central port 11a. A coiled eX- pansion spring 11b tends to move the valve member 11 toward its seat upon the upper end of the port 11, and the tension of said spring is'arranged to be varied at will by means of a suitable adjusting screw 11e .mounted in the upper section of the casing. The chamber 10 is arranged to communi-- cate by way of a port 14 controlled by a manually operated' valve 14a, with an annular chamber 15 formed by a jacket 154. Said chamber 15 is interposed in the return side of the pipe line Hleading to the'compressor, and itwill be seen that the chamber 1s arranged to be 'charged with ammonia gas discharged from the pipe line into the chamber 15. Preferably this is accomplished when all of the coils of the system have become frozen and a freezingy back-to the compressor initially occurs so that the gas with which the chamber 10 is charged is 1n a partially saturated condition. It will be noted also that the pressure of the charge in the chamber 10 will be line pressure, so as to bal'- ance the pressure upon the upper side of the diaphragm as it passes from the intermediate valve controlled port 11a-to the outlet 13 and into the pipe line. The spring 11b is adjusted so as to equalize any excess in the pressure of the gas in the chamber 10 due to radiation. Y

. .Each of the cooling or storage rooms I, I and I into which the refrigerant is discharged from the pipe line H is herein` shown as being similarly equipped with a cooling coil J, one end of which communicates with the pipe line H through a threeway valve K, and the other end of which ischarges into the Dine line. The valves K miams are specially constructed tor automatic operation by a temperature-controlled device indicated generally at L. i

lReferring rst to Fig. 3, each of the valves comprises a casing having opposed inlet and outlet ports 17 and 18 communicating with the main pipe line, and a second outlet port 19 communicating with the inlet side of the cooling coil J. Between the inlet and outlet ports 17 and 18 there is provided a partition 2.0 after the fashion of the ordinary globe valve, having a port or passage 21 therein axially alined with the outlet port 19. Between the ports 19 and 21 I arrange a valve member 22 having a stem 23 passing through the port 21 and guided at its upper end in a cap 24. At the mouth of the port 19 a seat 25 is provided for the valve when in its lowermost position, and a vbushing 26 screw-threaded into the opening forming the port 21 provides at its lower end a seat 27 for the valve member when in its uppermost position.

The device L for automatically operating the valve K comprises (Figj4) a casing 28 having a diaphragm 29 therein which is arranged to be subjected to pressure upon its underside received into the casing through a pipe 3Q communicating at its lower end with a pressure chamber 31 and a coil 32 communicating therewith. Said coil is closed at lits lower end so as to be adapted to c'on-l tain a liquid, such as liquid/ammonia, vai

porizing readily under variations in the and pivoted at the upper end of the stem is a lever 35 fulcrumed at 36 upon an upstanding arm 37 supported by the casing. The lever- 35 preferably carries an adjustable y weight 38 (Fig. 1) whereby the effect of the pressure upon the diaphragm as transmitted to the lever-35 may be varied at will. Preferably a coiled expansion spring 39 is interposed ,between the diaphragm at the lower wall of the casing 28 to balance the weight of' the stem 34 and associated parts.

The valve member 22 of the valve K is adapted for connection with the lever 35 for operation thereby, in the present instance by a rock-shaft 40 (Fig. 3) having rigid therewith a lever arm 41 (Fig. 1) which latter is connected by av link 42 with the free end of the lever 35. The shaft 4() is suitably journaled in onewall of the valve casing, and the lever arm 41 is secured thereto upon the outer side of the casing. Within the casing said shaft has rigid therewith a finger 43 o erating in a slot 44 in the valve stem 23. y this' means, it will be apparent, when the temperature in the storage or 22ih arrangement being such: th 4t fyvhenthe'y 'rooiiiqhas lbecome A sutii'c'liently c cool, flow of [the 'refrigerantv rooms are broken, and conversely,

4 be apparent compressor .is herein beyond its fulcruin to arm"4 5, for thejmovable contact 46 of a ment; of, the valve withw'thevseat the lower fou' let Win19?, midi Similarly" when" the `temperature,in the'cooling 4room rises ythe fvalve is Y operated toward" its' seat 27. so

` asv tovdirect the flou7 of the refrigerant hrough the coil J and vthence into the pipe 1ne.' Itis to ybe noted that the construction of the valve K and its arrangement in the sysi tem are such that the v alve member 22'is at all timessubjected to pressure upon both sides, so that it is' maintained substantially in a condition of balance.` Thus, when the valvelmember is in the position shown in Figlfgboth sides "are subjected to line pressure, since the'- discharge end of coil J is in constant communication with the pipe line; and' when the valve member is in its uppermost position, both sides thereof are subject to line pressure, since the outlet port 18 of the valve is in. constant communication with the line.l The importance of this balancedcondition in the present system will l'from the fact that the valve is thereby rendered capable of automatic operatinfdirectly by they thcrmostatic devicejL i The means for 'controlling the operation of thev electric motor B which actuates the associated with and operated bythe device Lof the several coolingrooms. Thus, ythe vlever of each of said devices (Fig. 4), i `nay provide a swinging switchhaving stationary. contacts 47 connectedwithopposite sides of the line C.' Said vstationary 4contacts47 may be 'convenie'ntly j supported .by a member 48 car- 'iied by 'the upstanding arm 37 on the casing 28. It will be apparent that the arrangementis such ythatwhen the temperature inoneof the'co'oling rooms falls to a predetermined point so as to cause the lever arm 35 to descend, the movable contact 46 is carried out of engagement with the stationary contacts 47 so as to open the switch. The motor circuit, however, remains closed until the switches 46, .47 of all the cooling when the temperature in one of the rooms rises, the switch is closed to re-start the motor and restore the system to operation.

Summarizing the operation of `my iinproved system: The expansion valve G is set so as to supply refrigerant to the pipe line at 'a pressure determined by the number of storage chambers to be cooled. Obviously it the' 'device L correbey extended somewhat ther.

is desirablethatall of the coils be frozen asA quickly as possible so v that sure yis preferablyrelativelyhigh. Until all the refrigerant 'of `the A coils 1 are thu'sf frozen, returning to 'the 'compressor throughthe Vreturn Side of thepipel line H, vthat Iin passing through the'chamber lsursage of'therefrigerant into the pipe line.

lVhen, however, all of the coils become frozen, the lowered temperature of the returning-refrigerant is imparted to the gas in the chamber 10v and the decreased pressure causes the valve 11 to close partially, thus automatically reducing the pressure of the 'refrigerant discharged into the line in accordance with the changed requirements. It

the initial presas to hold the"l fis heated, so v 'rounding the lower section Sof the con.- i Atrolling valve easiiig, the pressure ofthe .gasr in the chamber '1 0 is such valve member l11 open, allowing free paswill be observed that the returning refrigery ant in passing through the chamber 15 surrounds the chamber 10 so that the gas in the latter is subjected to the temperature of the refrigerant only and is uninfluenced by the y room temperature; Also the gas is not influenced by the temperature of the refrigeri ant in the upper portion of the casing due passing to the coils and the temperature of the refrigerant returning from the coils, and

if subjected to variable disturbing influences f Vsuchas the temperature of the chamber being cooled or the temperature of the refrigerant passing to the coils, the valve will obviously fail to operate as intended.

Should `one of the storage rooms become sutliciently cooled, the pressure required to supply the remaining rooms falls still fur- The result is that the temperatureof the refrigerant returning to the compressor is lowered, and the effect4 of such lowered temperature on the gas in the chamber 10 of the controlling valve member 11 to restrict further the ow of refrigerant to the pipe line substantially in accordance with the changed requirement. The result, it will be apparent, is a saving in the power consumed in providing the necessary refrigeration for the several rooms. In the first place all of the coils, because of the initial high pressure of the refrigerant discharged intothe pipe line, become frozen in a. relatively short time, so that the system rapidly becomes operative in its entirety;y

In the second place, by reducing the ressure ered and the system continues in Opem; i310 tion at maximum eiiciency, effecting a savvalve is such as to cause the.'

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ing in the power consumption, avoiding injury tothe compressor by preventing the return thereto of liquid ammonia caused by an excessive freezing back; and insuring that the gas shall be returned to the com-v partially saturated ing into the cooling coil J, ultimately eutting ofi' the'fiow of refrigerant to such coil entirely. Simultaneously with the closing of the port 19 by the valve member, port 21 is opened to allow the refrigerant to pass through thel valve effectively cutting out the coil J. As a result, .the temperature of the refrigerant returned to the compressor falls, and in passing through thechamber formed by the jacket 15, causes the pressure in the chamber to decrease and effecting a restriction of the valve opening accordingly.

Finally, when the several rooms are reduced to the desired temperatures, the switches 46. 47 are operated by the devices y L to open the motor line circuit C, effecting the stoppage of the motor.

It willv thus be observed that I have through the provision of relatively' simple control devicesrendered it possible to operate `a refrigeration system entirely autol matically and in such a way as to increase substantially the efficiency of the system as whole, to accomplish a higher compressor efficiency and avoid injury to the compressor. At the same time, the elimination of manual control results in a. saving in time and labor, while loss ldue to the production of temperatures too low or too high, occurring through carelessness on the part of an attendant, is-avoided. The use of an `|expansion or reducing valve in combination with a control valve is advantageous be'- eause a sudden or sharp reduction in pressure such as would be effected by the use of a single valve would result in a wire drawing of the refrigerant which is objectionable because of an attendant cutting action on the.,

compressor supplying liquid refrigerant to said feed line, a valve for expanding the liquid refrigerant into said line at constant pressure, a succession of refrigerating coils each having its inlet. and outlet communicating with said feed line, individual thermo'- static valves controlling the flow of refrigerant to each of said coils, a common return line leading from said feed line beyond the outlet of the last coil, and a control valve interposed in said feed line between said expansion valve and the first refrigerating coil, said valve being adapted to regulate the flow of refrigerant to all of said coils solely under the control of the temperature in said return line.

2. In a refrigeration system, the combination with a feed line, a return line, and a plurality of coils adapted to be shunted into said feed line, of a source of compressed n frigerant, a valve for frigerant to a constant point, and a valve operable under the control of the temperature in said return line for further expanding the refrigerant suppliedto said feed line and regulating the flow thereof to said coils.

In testimony whereof, I have hereunto affixed my signature.

GEORGE HILGER.

expanding said re- 

